479 
The diameter of the largest specimens was estimated at 177 mm.; 
the imperfect living chamber in this was somewhat less than one-half 
of a volution in length. ‘The transverse diameter of the septal floor 
of this chamber was, estimating by half measurement, more than 
74 mm., the ventro-dorsal about 50 mm. ‘The siphuncle from 
which the measures were taken may not have been in the centre in 
this specimen, so the measurements of the transverse diameter may 
be faulty. The living chamber in this and the next specimen de- 
scribed reached well into the first half of the fifth volution, as esti- 
mated by careful comparison with the young specimen above de- 
scribed and figured. 
The most perfect fossil of this species was 140 mm. in diameter. 
The living chamber showing lines of what appeared to be the 
rugged edge of an aperture was just one-half of a volution in length. 
The suture of the septal floor was similar to that described above. 
The transverse diameter at the septal floor was about 60 mm., the 
diameter through the side about 31 mm. ‘The transverse diameter 
midway in this chamber became nearly 74 mm., and the diameter 
through the side 40 mm. 
Near the aperture the ventro-dorsal diameters continued to in- 
crease and the transverse decreased, or in other words the aperture 
was not so broad as the middle of the chamber which was slightly 
expanded. ‘The shell was enormously thick on the venter, showing 
age, it was near the middle about 2 mm. in thickness, and near this 
aperture 6.5 mm. in thickness. The lines of growth indicated a very 
large, broad and deep hyponomic sinus al broad lateral crests, but 
these were not distinctly seen. 
The siphuncle, in the specimen 177 mm. in diameter, reached 
the large size of 11 mm. at the septal floor, and less than one-half of 
a volution younger was 6.5 mm. in diameter. The septa were only 
6 to 6.5 and 7.mm. apart as measured on the siphuncle at this age 
near the living chamber. ‘They were nearer together than in adults 
at this gerontic stage as is usual in outgrown specimens. The last 
two sutures of the smaller fossil described as 140 mm. in diameter 
were 7 mm. distant, which is probably the average distance of a 
full-grown shell, judging also by the remains of an isolated siphuncle 
in the collection belonging to this species. 
LITOCERAS BIANGULATUM, Ni. Ss. 
Loc., Pt. Rich., Newfoundland. 
This shell appears in the collection at Ottawa under the name of 
